Fixed pitch propellers have been used since the beginning of powered flight and are still used today because of their simplicity and weight advantage. One of the pitfalls of fixed pitch propellers is that they operate efficiently only at one propeller speed and one flight speed. Efforts on variable pitch propeller design started with the Frenchman named J. Croce-Spinelli in 1871. But it took the effort of several more inventors in different countries to bring the variable pitch propeller to aviation in the 1930's. This lead to significant aircraft performance improvements with respect to cruising speed, high altitude operations and short field takeoff ability. Later the constant speed propeller was introduced which automatically adjusts the pitch of the propeller, making it more user friendly for flight crews. The early variable pitch propellers were mechanically operated and prone to fail after a few operating hours due to material fatigue. This lead to the design of hydraulically operated variable pitch and constant speed propellers, which are still found in most of today's high performance airplanes.
The small-scale Unmanned Aerial Vehicles (UAVs), also referred to as Unmanned Aerial Systems (UASs), in military reconnaissance operations are still using fixed pitch propellers which can be exchanged based on mission requirements. The reason for the use of fixed pitch propellers is system simplicity, weight savings and unavailability of a viable alternative.